Acetic Anhydride → (S)-N-[[3-(3-Fluorophenyl)-2-oxo-5-oxazolidinyl]methyl]acetamide

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Reaction Steps

A mixture of (R)-[3-(3-fluorophenyl)-2-oxo-5-oxazolidinyl]methyl azide (PREPARATION 16, 8.200 g, 34.71 mol) in ethyl acetate (100 ml) is treated with palladium on carbon (10%, 0.820 g) under nitrogen. The atmosphere is then replaced with hydrogen (balloon) via repeated evacuation and filling. After stirring under hydrogen for 17 hr, TLC in methanol/chloroform (5/95) reveals the azide starting material is consumed. The atmosphere is replaced with nitrogen and then pyridine (6 ml) and acetic anhydride (4.1 ml, 43.40 mmol) are added to the reaction mixture. The reaction mixture is stirred for 1 hr at 20-25° and then filtered through Celite, washing the pad with ethyl acetate. The filtrate is concentrated under reduced pressure and the residue taken-up in dichloromethane. The addition of ether affords a precipitate. After standing in the refrigerator overnight the solids are collected by vacuum filtration, washed with cold hexane, and dried under reducedpressure to give the title compound as a solid. The crude product is purified by chromatography over silica gel, eluting with methanol/chloroform (5/95). The appropriate fractionsare pooled and concentrated to give the title compound, mp 140.0-140.5°; [α]25D -6.6° (c 1.0, CHCl3).

Provenance & Evidence